This invention relates to a safety device for the closing edge of the door leaf of a door or similar means for closing building entrances or doorways.
It is known to attain, with the aid of door end profiles extending over the width of the door leaf closing edge facing towards the closing direction, not only a sealing effect in the closing position vis a vis the ground but also a safety function of such a kind that an object or person unintentionally getting in the path of motion of the door leaf closing edge produces a signal by compressing the door end profile--usually a hollow section rubber--which signal stops or reverses the door leaf motion which is necessary for reasons of safety, especially with motor-driven door leaves.
In a known construction the door end profile has two electrically conducting paths over its length which upon compression of the ledge or strip by an object engage one another and thus close a contact which triggers the above-mentioned signal. However, maintaining such a contact ready to operate is problematic in practical use of the strip and over the long service life of such a door because oxidation can occur due to atmospheric influence, and penetration of dirt cannot be excluded so that safety of operation of such a door end profile is insufficient (e.g. DE-OS 26 43 505).
In a known construction of the above-mentioned type pneumatic operation is provided in such a manner that upon compression of the air-filled hollow space of the door end strip, formed as a hollow section rubber, a pressure wave signal is generated which, taken off on one end of the hollow space, is supplied to a pressure chamber having a diaphragm which, as consequence, is subject to an excursion and thus triggers the stop or reversing signal. When the hollow section rubber is damaged, for example, cut open by a sharp-edged object, safe operation of such a door end profile is at least put into question. To monitor such a profile or strip as to its readiness for service in the rota of the door leaf opening and closing movements, one has already provided a limit stop on one of the end positions of the door leaf which triggers a monitoring signal in the form of an air pressure pulse (e.g. DE-GM 85 35 506.2). Apart from the fact that the compression of the strip and/or a special strip joining piece or the like taking place in the rhythm of the door movement leads to material fatigue and consequently to lacking operation safety, any monitoring as to readiness for operation of the closing edge safety device during the movement of the door leaf does not take place so that any damage to the hollow section rubber, e.g. by being cut open, which may occur in the course of such a movement and this without the generation of an emergency pulse interpreted as such one, may lead to the loss of operation safety and consequently of the switch-off function.